Its nice to hear about your new tank. That's a a fun size to work with.
Make sure you have a powerful enough heater for the tank, firstly.
If you want, consider adding more live plants. Theyre a great addition to any tank and you can have a lot of fun with them in a big tank. Consider getting a nice piece of driftwood (real driftwood, make sure its hardwood or it will rot!) You can have them grow off this and it would look wonderful.
Some easier plants are java fern, anubias, anacharis, hornwort, cabomba (tank less than or at 77'), wisteria, moneywort, and multiple others. Many of these plants are floating but can be weighted down, too.
Consider getting a few larger terracotta pots to add as cute hidey places. You can even tie down the java fern or anubias to them and it will root to it. Make sure the hole on the bottom is closed up.
Silk plants work great in tanks, Petco sells its own line of them- theyre not too expensive and are good looking and safe, IME. I like them.
If you want shrimp, you might wanna let the tank cycle first (if you plan on doing so), because Ive heard they are sensitive to toxins in the tank. You might wanna look into sand or a fine gravel to put in.
Good luck, we'd love to see pics of your ideas as well as the final product!